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arXiv 2409.12232astro-ph.GA
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揭示极端紫外发射线天体中的高红移AGN族群

UNCOVERing the High-redshift AGN Population among Extreme UV Line Emitters

Helena Treiber, Jenny Greene, John R. Weaver, Tim B. Miller, Lukas J. Furtak, David J. Setton, Bingjie Wang, Anna de Graaff, Rachel Bezanson, Gabriel Brammer, S… 展开作者

Helena Treiber, Jenny Greene, John R. Weaver, Tim B. Miller, Lukas J. Furtak, David J. Setton, Bingjie Wang, Anna de Graaff, Rachel Bezanson, Gabriel Brammer, Sam E. Cutler, Pratika Dayal, Robert Feldmann, Seiji Fujimoto, Andy D. Goulding, Vasily Kokorev, Ivo Labbe, Joel Leja, Danilo Marchesini, Themiya Nanayakkara, Erica Nelson, Richard Pan, Sedona H. Price, Jared Siegel, Katherine Suess, Katherine Whitaker

AI总结:

本研究利用JWST的UV发射线诊断,在UNCOVER高红移星系样本中识别出12个极端发射线天体,发现5个He II发射体为最强AGN候选体,并揭示了一个新的宽线AGN,为高红移AGN族群研究提供了新约束。

摘要:

JWST揭示了多种新的高红移($z\sim4-11$)AGN和极端恒星形成星系族群,这些族群挑战了现有模型。本文利用静止系UV发射线诊断来识别AGN候选体和其他特殊电离源,补充了以往主要关注宽线AGN的研究。在205个具有NIRSpec/PRISM后续观测且$\mathrm{z_{spec}}>3$的UNCOVER星系母样本中,我们识别出12个C IV、He II和C III]发射体。其中三个星系还表现出明显的N III]和/或N IV]谱线。利用PRISM的静止光学和UV综合覆盖,我们使用样本的[O III]/H$β$分布限制发射线模型空间,显著减少了UV诊断中AGN与恒星形成模型的重叠。随后我们发现五个He II发射体是最强的AGN候选体,两个[Ne V]探测和一个Chandra X射线探测进一步支持了这一结论。我们的Balmer线拟合还在z=6.87处揭示了一个新的宽线AGN。我们无法稳健量化该样本中的AGN比例,但注意到接近20%的$\mathrm{M_{*}>2\times10^{9}\\,M_{\odot}}$母样本星系是AGN候选体。与AGN和恒星形成光致电离模型均相符的低质量线发射体,比母样本具有更紧凑的尺寸和更高的比恒星形成率。对这些UV线发射体进行更高分辨率和更深度的观测,应能对$z > 3$处受遮蔽的AGN比例提供更强约束。

英文摘要:

JWST has revealed diverse new populations of high-redshift ($z\sim4-11$) AGN and extreme star-forming galaxies that challenge current models. In this paper, we use rest-frame UV emission-line diagnostics to identify AGN candidates and other exceptional ionizing sources, complementing previous studies predominantly focused on broad-line AGN. From a parent sample of 205 $\mathrm{z_{spec}}>3$ UNCOVER galaxies with NIRSpec/PRISM follow-up, we identify 12 C IV, He II, and C III] emitters. Three of these galaxies also exhibit clear N III] and/or N IV] lines. Leveraging the combined rest-optical and UV coverage of PRISM, we limit the emission-line model space using the sample's [O III]/H$β$ distribution, significantly decreasing the overlap between AGN and star-formation models in the UV diagnostics. We then find that the five He II emitters are the strongest AGN candidates, with further support from two [Ne V] detections and one X-ray detection from Chandra. Our Balmer line fits also reveal one new broad-line AGN at z=6.87. We cannot robustly quantify the AGN fraction in this sample, but we note that close to 20% of $\mathrm{M_{*}>2\times10^{9}\,M_{\odot}}$ parent sample galaxies are AGN candidates. The lower-mass line emitters, which are consistent with both AGN and star-forming photoionization models, have more compact sizes and higher specific star formation rates than the parent sample. Higher-resolution and deeper data on these UV line emitters should provide much stronger constraints on the obscured AGN fraction at $z > 3$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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